There were also so-called "learning codes" that overlapped substantially with the introduction of rolling codes. Think fixed-code remotes with a random preprog

There were also so-called "learning codes" that overlapped substantially with the introduction of rolling codes. Think fixed-code remotes with a random preprogrammed code instead of dip switches. Chamberlain's "billion code" is representative. They have to be paired with the opener receiver in the same way as rolling code remotes.